Question

Molten lava pours from a volcano in Hawaii. After a few hours, the liquid lava hardens into a shiny gray rock.

Which phase change has taken place?

Select one:
a. melting
b. freezing
c. boiling
d. condensation

Answer 1

The answer is freezing (Option B)

Step-by-step explanation:

To begin with, it is important to note that lava flowing from Hawaiian volcanoes are not sticky but very runny. They cool down or freeze after flowing a long way.

Since the lava is not sticky (because it is not thick), it means they are thin and prone to freezing or cooling immediately when the flow stops. Upon freezing, the lava forms crystal rocks (shiny in texture and gray in color) that are not big.